Solar Physics

, 293:49 | Cite as

Sensitivity Monitoring of the SECCHI COR1 Telescopes on STEREO

  • William T. Thompson


Measurements of bright stars passing through the fields of view of the inner coronagraphs (COR1) on board the Solar Terrestrial Relations Observatory (STEREO) are used to monitor changes in the radiometric calibration over the course of the mission. Annual decline rates are found to be \(0.648 \pm 0.066\)%/year for COR1-A on STEREO Ahead and \(0.258 \pm 0.060\)%/year for COR1-B on STEREO Behind. These rates are consistent with decline rates found for other space-based coronagraphs in similar radiation environments. The theorized cause for the decline in sensitivity is darkening of the lenses and other optical elements due to exposure to high-energy solar particles and photons, although other causes are also possible. The total decline in the COR-B sensitivity when contact with Behind was lost on 1 October 2014 was 1.7%, while COR1-A was down by 4.4%. As of 1 November 2017, the COR1-A decline is estimated to be 6.4%. The SECCHI calibration routines will be updated to take these COR1 decline rates into account.



The author would like to thank Chris St. Cyr for several helpful suggestions, and Nathan Rich for help with the thermal history. The author would also like to thank the anonymous referee for several helpful suggestions. This work was funded under NASA Contract NNG06EB68C. The STEREO/SECCHI data used here are produced by an international consortium of the Naval Research Laboratory (USA), Lockheed Martin Solar and Astrophysics Lab (USA), NASA Goddard Space Flight Center (USA) Rutherford Appleton Laboratory (UK), University of Birmingham (UK), Max-Planck-Institut für Sonnensystemforschung (Germany), Centre Spatiale de Liége (Belgium), Institut d’Optique Théorique et Appliquée (France), and Institut d’Astrophysique Spatiale (France).

Disclosure of Potential Conflicts of Interest

The author declares that he has no conflicts of interest.


  1. Bein, B.M., Temmer, M., Vourlidas, A., Veronig, A.M., Utz, D.: 2013, The height evolution of the “true” coronal mass ejection mass derived from STEREO COR1 and COR2 observations. Astrophys. J. 768, 31. DOI. ADS. ADSCrossRefGoogle Scholar
  2. Buffington, A., Morrill, J.S., Hick, P.P., Howard, R.A., Jackson, B.V., Webb, D.F.: 2007, Analysis of the comparative responses of SMEI and LASCO. Proc. SPIE 6689, 66890B. DOI. ADSCrossRefGoogle Scholar
  3. Colaninno, R.C., Howard, R.A.: 2015, Update of the photometric calibration of the LASCO-C2 coronagraph using stars. Solar Phys. 290, 997. DOI. ADS. ADSCrossRefGoogle Scholar
  4. Ducati, J.R.: 2002, VizieR online data catalog: catalogue of stellar photometry in Johnson’s 11-color system. VizieR Online Data Catalog 2237. ADS.
  5. Frazin, R.A., Vásquez, A.M., Thompson, W.T., Hewett, R.J., Lamy, P., Llebaria, A., Vourlidas, A., Burkepile, J.: 2012, Intercomparison of the LASCO-C2, SECCHI-COR1, SECCHI-COR2, and Mk4 coronagraphs. Solar Phys. 280, 273. DOI. ADS. ADSCrossRefGoogle Scholar
  6. Freeland, S.L., Handy, B.N.: 1998, Data analysis with the SolarSoft system. Solar Phys. 182, 497. DOI. ADS. ADSCrossRefGoogle Scholar
  7. Gardès, B., Lamy, P., Llebaria, A.: 2013, Photometric calibration of the LASCO-C2 coronagraph over 14 years (1996 – 2009). Solar Phys. 283, 667. DOI. ADS. ADSCrossRefGoogle Scholar
  8. Howard, R.A., Moses, J.D., Vourlidas, A., Newmark, J.S., Socker, D.G., Plunkett, S.P., Korendyke, C.M., Cook, J.W., Hurley, A., Davila, J.M., Thompson, W.T., Cyr, O.C.S., Mentzell, E., Mehalick, K., Lemen, J.R., Wuelser, J.P., Duncan, D.W., Tarbell, T.D., Wolfson, C.J., Moore, A., Harrison, R.A., Waltham, N.R., Lang, J., Davis, C.J., Eyles, C.J., Mapson-Menard, H., Simnett, G.M., Halain, J.P., Defise, J.M., Mazy, E., Rochus, P., Mercier, R., Ravet, M.F., Delmotte, F., Auchere, F., Delaboudiniere, J.P., Bothmer, V., Deutsch, W., Wang, D., Rich, N., Cooper, S., Stephens, V., Maahs, G., Baugh, R., Mcmullin, D.: 2008, Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI). Space Sci. Rev. 136, 67. DOI. ADS. ADSCrossRefGoogle Scholar
  9. Kaiser, M.L., Kucera, T.A., Davila, J.M., St. Cyr, O.C., Guhathakurta, M., Christian, E.: 2008, The STEREO mission: An introduction. Space Sci. Rev. 136, 5. DOI. ADS. ADSCrossRefGoogle Scholar
  10. Tabur, V., Bedding, T.R., Kiss, L.L., Moon, T.T., Szeidl, B., Kjeldsen, H.: 2009, Long-term photometry and periods for 261 nearby pulsating M giants. Mon. Not. Roy. Astron. Soc. 400, 1945. DOI. ADS. ADSCrossRefGoogle Scholar
  11. Tappin, S.J., Eyles, C.J., Davies, J.A.: 2015, Determination of the photometric calibration and large-scale flatfield of the STEREO Heliospheric Imagers, II: HI-2. Solar Phys. 290, 2143. DOI. ADS. ADSCrossRefGoogle Scholar
  12. Tappin, S.J., Eyles, C.J., Davies, J.A.: 2017, On the long-term evolution of the sensitivity of the STEREO HI-1 cameras. Solar Phys. 292, 28. DOI. ADS. ADSCrossRefGoogle Scholar
  13. Thernisien, A.F., Morrill, J.S., Howard, R.A., Wang, D.: 2006, Photometric calibration of the LASCO-C3 coronagraph using stars. Solar Phys. 233, 155. DOI. ADS. ADSCrossRefGoogle Scholar
  14. Thompson, W.T., Reginald, N.L.: 2008, The radiometric and pointing calibration of SECCHI COR1 on STEREO. Solar Phys. 250, 443. DOI. ADS. ADSCrossRefGoogle Scholar
  15. Thompson, W.T., Wei, K., Burkepile, J.T., Davila, J.M., Cyr, O.C.S.: 2010, Background subtraction for the SECCHI/COR1 telescope aboard STEREO. Solar Phys. 262, 213. DOI. ADS. ADSCrossRefGoogle Scholar
  16. Thompson, W.T., Davila, J.M., St. Cyr, O.C., Reginald, N.L.: 2011, STEREO SECCHI COR1-A/B intercalibration at 180° separation. Solar Phys. 272, 215. DOI. ADS. ADSCrossRefGoogle Scholar
  17. von Rosenvinge, T.T., Reames, D.V., Baker, R., Hawk, J., Nolan, J.T., Ryan, L., Shuman, S., Wortman, K.A., Mewaldt, R.A., Cummings, A.C., Cook, W.R., Labrador, A.W., Leske, R.A., Wiedenbeck, M.E.: 2008, The High Energy Telescope for STEREO. Space Sci. Rev. 136, 391. DOI. ADS. ADSCrossRefGoogle Scholar
  18. Wang, T., Reginald, N.L., Davila, J.M., Cyr, O.C.S., Thompson, W.T.: 2017, Variation in coronal activity from solar cycle 24 minimum to maximum using three-dimensional reconstructions of the coronal electron density from STEREO/COR1. Solar Phys. 292, 97. DOI. ADS. ADSCrossRefGoogle Scholar

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© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.ADNET Systems Inc.NASA Goddard Space Flight CenterGreenbeltUSA

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